How To Specify Resistive Load Bank Generators

Diesel engines (the main movers located on a diesel generator set) are designed to operate with a minimum amount of load. This ensures that they will perform at an exceptional level without any problems. The manufacturer determines how many loads the engine needs, but it’s important to point out that the average range is 40% To 50% of the kilowatt rating. Studies show the diesel engines perform better in the 70% to 80% range of rated output. At this range, they provide a greater output.

A load bank helps a diesel engine get to an acceptable operating temperature fast, and it helps minimizes the chances of wet stacking taking place. Wet stacking is a unique condition that occurs when you run an engine in an unloaded condition, or continuously use it at less than the industry’s minimum load level. When wet stacking takes place, the fuel injection tip will start to carbonize and cause problems for the fuel spray problem. Wet stacking is one of the reasons why important centers buy a new load bank generator each year.

Why Emergency Power is Important

Consulting engineers with experiencing in emergency power equipment are aware that installations for important facilities like hospitals must meet NFPA 110 standards to satisfy the National Electrical Code. If you read the NFPA 100 details closely, you will see that Section 7.13 specifies the type and length of load testing for generator sets for mission critical facilities.

The Y2K and 2003 blackout taught us that operating emergency power can save lives. Fortunately, load bank technology today provides inexpensive solutions to make sure that diesel generator sets are loaded correctly. Monthly load bank testing can determine if the diesel generator is putting out enough power.

Specifying Load Banks


The first step of specifying load banks require you to get the voltage and kilowatt rating of the prospective load bank. In some instances, clients want the load bank to have the same kilowatt rating as the generator set. They know that many generator sets are built for future growth. This is the primary reason why clients will spare no cost when it comes to adding more equipment like UPS systems, drives, or high-performing computers. The generator sets will be able to handle extra equipment.

For the next step, you must find out what type of load bank is suitable for the application. The three common resistive load banks types in the market are radiator mount, portable, and permanent. Let’s take a close look at them.

Radiator Mount

A radiator mounted load bank does not have cooling fan controls. Many companies choose the radiator mounted load bank generator because it’s cost-effective. It is designed to be attached on the radiator of the genset, and it depends upon the airflow in the radiator to keep its load elements cool. The unit is thirteen inches deep, and it will keep the back-pressure on the radiator in check.

It is vital for you to know that a radiator mounted load bank is a complimentary load to the genset. An experienced engineer knows that a 100% rated radiator mounted load bank will overheat the generator set. The average radiator mounted load bank is 50% to 70% of the generator set kilowatt capacity. If a client needs a 100% rated load bank, a freestanding permanent load bank will be the best option.

Radiator mounted load banks are placed in the warm exhaust of the radiator. It needs to be made out of heat resistant material. The primary aim is to avoid overworking the load bank. You don’t want the load bank to behave like a heat sink for the radiator. The engineer should focus on using load banks that are made out of durable aluminum steel. Galvanized steel is not recommended for any project related to a center that provides important and emergency services.

The radiator mounted load bank should have a remote control panel, an automatic load dump, third-party certification. It should also be manufactured out of weatherproof materials. Weatherproof materials will protect it from the heat, rain, and snow. New enclosures on the market can be mounted on the enclosure. Buying a new enclosure is one sure-fire way of protecting an expensive investment.

Portable Units

Portable units are starting to gain more popularity in the load bank generator industry. Portable units are designed for indoor usage. They have basic controls and metering systems. They can also load at several different voltages. With casters at hand, they can be moved to any location with ease. One kilowatt portable load bank can be used to test them. Load bank testing is the easiest way of determining if the portable unit is working well.

Permanent Load Banks

Permanent load banks are the best option when the application permits installation on a rooftop or a sturdy concrete pad. If the client needs a 100% load on its generator set, permanent load banks should not be overlooked. Freestanding load banks come with basic cooling fans and they do not put any static pressure on the generator. This feature helps permanent load banks last for several years. It is also vital to mention that permanent load banks can perform in any type of weather. Snow, heavy rain, or hot weather will not slow it down. However, it’s important for the engineer to make certain that the unit is protected with outdoor weatherproof construction and a third-party certification (CE, CSA, UL, or Canadian UL).

Permanent units normally use a convenient remote control panel. The remote control panel can be placed anywhere from 50 to 250 feet away from the load bank. It would be a grave mistake to operate a permanent load bank without an internal strip heater that gets power from an exclusive voltage source (120 V, 1-phase, 60 Hz). The strip heater will kick on when the temperature gets below 50 F.

Final Conclusion

The engineer must get the above information from the client. This helps the engineer to select a load bank generator that will be ideal for the client. The engineer must also make certain that the load bank meets local, state, and federal codes. Most manufacturers of load banks offer downloadable specifications. The engineer simply plugs in the required voltage, kilowatt, and any other details that will serve the client’s needs.

Load bank testing is one important matter that engineers cannot afford to ignore. This helps ensure that the load bank will operate well for the client. A monthly load test will determine if the client has reliable back-up power. The three most popular types of load banks (permanent, radiator, and portable) are well-known for meeting standard requirements without increasing the client’s monthly overhead, or letting them down during an emergency situation.